Let’s call it the theory of receptivity. It’s the idea, often cited by young people in their case against the relevance of even marginally older people, that one’s taste—in music or film, literature or fine cuisine—petrifies during life’s peak of happiness or nadir of misery. Or maybe it’s not that simple. Maybe a subtler spike on the charts—upward, downward, anomalous points in between—might qualify, so long as it’s formative. Let’s say that receptivity, anyway, can be tied to the moments when, for whatever reason, a person opens herself to the things we can all agree make life worth living in a new and definitive way, whether curiosity has her chasing down the world’s pleasures, or the world has torn a strip from her, exposing raw surface area to the winds.